Geodetic Observations Reveal Near‐Zero Uplift Rates in the Transantarctic Mountains: Implications of Surface Mass Loading Deformation

Abstract The exposed bedrock of the Transantarctic Mountains (TAM) provides rare opportunity to constrain present‐day Glacial Isostatic Adjustment (GIA) in East Antarctica, with impacts on Gravity Recovery and Climate Experiment (GRACE) and other estimates of ice‐mass change. In this study, we use Global Positioning System (GPS) displacement time series to provide new observations of uplift in the TAM region. We demonstrate that the deformation signal due to Surface Mass Balance (SMB) loading manifests as a multi‐year apparent change in the vertical linear trends—that is, a change in velocity. After correcting for SMB‐induced elastic deformation, we find that most GPS sites in the TAM region exhibit velocities approaching zero, with a median rate of 0.67 mm/yr. This is lower than forward GIA models predict, suggesting revisions to regional ice history and/or Earth models are required and current GIA models bias estimates of present‐day ice sheet mass change.